Hereditary spastic paraplegia (HSP), also known as familial spastic paraparesis, refers to a group of inherited disorders that involves weakness and spasticity, which is stiffness of the legs. These symptoms get worse over time. Early in the disease, there may be mild trouble walking and stiffness. These symptoms typically get worse slowly until a cane, walker, or wheelchair is needed.

The progressive lower limb spasticity and weakness are the main features of “pure” HSP. Complicated forms of HSP may include other symptoms:

• Impaired vision due to cataracts and problems with the optic nerve and retina of the eye
• Ataxia, which is a lack of muscle coordination
• Epilepsy
• Cognitive impairment
• Peripheral neuropathy, damage to the nerves outside of the brain and spinal cord
• Deafness

HSP is diagnosed mainly by neurological exam and testing to rule out other disorders.

Several genetic mutations have been identified that are linked to various forms of HSP, and specialized genetic testing and diagnosis are available at some medical centers. HSP has several forms of inheritance. Not all children in a family will necessarily develop symptoms, but they may be carriers of the abnormal gene. Depending on the HSP gene involved, symptoms may begin in childhood or adulthood.

There are no treatments to prevent, slow, or reverse HSP. Treatments such as muscle relaxers can sometimes relieve spasticity. Regular physical therapy is important for muscle strength and to keep range of motion.

The outlook for people with HSP varies. Some people are significantly limited and others have only mild disability. Most people with pure HSP have a normal life expectancy.

The hallmark feature of hereditary spastic paraplegia is progressive weakness and spasticity (stiffness) of the legs. Symptoms typically develop between the second and fourth decades (although earlier and later presentation has been described). Early in the disease course, there may be mild gait difficulties and stiffness. These symptoms typically slowly progress so that eventually, individuals with HSP may require the assistance of a cane, walker, or wheelchair. In some cases, additional symptoms may occur. These can include:

• impaired vision
• ataxia
• urinary urgency and frequency
• hyperactive reflexes
• Babinski's sign
• difficulty with balance
• epilepsy
• cognitive impairment
• peripheral neuropathy
• deafness

• Characteristic clinical symptoms of slowly progressive weakness and stiffness in the legs often accompanied by urinary urgency
• Neurologic examination demonstrating damage to the nerve paths connecting the spinal cord and the brain (corticospinal tract), such as spastic weakness, exaggerated reflexes, typically associated with bilateral extensor plantar responses; often accompanied by a mild inability to sense vibration in the lower part of the legs and muscle changes of the urinary bladder
• Family history shows a pattern of inheritance that is either autosomal dominant, autosomal recessive, or X-linked recessive
• Exclusion of other disorders that cause spasticity and weakness in the legs
• Identification of a disease-causing mutation in an HSP-causing gene; such testing is increasingly available and can confirm the diagnosis of HSP.

The prognosis for individuals with HSP varies. Some individuals are very disabled and others have only mild disability. The majority of individuals with uncomplicated HSP have a normal life expectancy.